A perfect java blog

A Public Vs. Nonpublic Classes

6 March,2009Narayan Gopal Maharjan

Probably we used to declare the method and class as a public .
But the there is also the classes where there is no any public
or any private .
We can make two or many classes in a single class file.
* But when declaring numerous class the class file must contain
at least one public class whose class must match to class file
name.A simple class containing two class with it’s package :
[sourcecode=’java’]
//package
//Test1.java
package Test1;
public class Test1{…}
class Test2{…}[/sourcecode]Another class containing with two class with pacakage:
[sourcecode=’java’] //package
// X.java

package X;
public class X{….}
class Y{….}[/sourcecode]
At this time we can’t instantiate any variable from X.java to Test1.java Because it’s been blocked by a wall of Package.
A structure diagram of above file will looks like this:

We can make a link between these files:
By importing its package from one class to another.
[sourcecode=’java’]//Test1.java
//package
import X.*;

package Test1;
public class Test1{…}
class Test2{…}[/sourcecode]
Now the structure looks like this:

The above code doesn’t care about the non public class Y of X.java because of it’s non public feature. The public class Test1.java can’t make a object even if we import the package X.